What first time expenses in California caught you off guard?

I'm learning about the California firearm ownership process and was curious about the additional requirements and expenses that new owners sometimes overlook.

Things like:

FSC requirements DROS paperwork Storage requirements Waiting period logistics Range equipment or training Any other first-time ownership expenses or requirements

Were there any parts of the process that surprised you or that you wish you had known beforehand?

Just trying to understand the overall process and requirements for new firearm owners in California.